1. Field of the Invention
The present invention relates to a process cartridge detachably installed in an image forming apparatus such as a copying machine, a printer, a facsimile, and a plotter, or such as a multifunction peripheral having a plurality of these functions, and also relates to the image forming apparatus.
2. Description of the Related Art
In image forming apparatuses such as a copying machine, a printer, a facsimile, and a plotter, or such as a multifunction peripheral having a plurality of these functions, an electrostatic latent image formed on a photoconductor serving as an image bearer or a latent image bearer is subjected to visualization processing using toner in a developer supplied from a developing device. A toner image subjected to visualization processing is transferred to a recording sheet and the like serving as a sheet recording medium and is further subjected to fixing processing to be output as a copy. The developing device used for visualization processing of the electrostatic latent image may be configured to use a one-component developer including only toner. In addition, the developing device may be configured to use a two-component developer including toner and a carrier.
Known examples of the developing device using the two-component developer include a magnetic brush developing device configured such that a magnetic brush is formed on a surface of a developing sleeve serving as a developer bearer incorporating a plurality of magnetic poles by causing the toner in the two-component developer to adhere to a magnetic carrier to be napped. The developing sleeve supporting the magnetic brush on the surface thereof rotates to cause the toner on the supported magnetic brush to be brought into contact with an electrostatic latent image formed on a surface of the photoconductor serving as a latent image bearer. With this configuration, the toner in the developer is transferred to the electrostatic latent image by electrostatic attraction caused between the toner and the electrostatic latent image. Hereinafter, the developing sleeve may also be referred to as a “developing roller”. Accordingly, the developing roller functions as the developer bearer.
In a two-component developing process, regarding a toner amount scooped by the developing sleeve for causing a desired amount of toner to adhere to the photoconductor, it has been known that accuracy of a distance between the developing sleeve and the photoconductor set to cause the toner to electrostatically adhere to the photoconductor is important.
The distance between the developing sleeve and the photoconductor is often fixed by a pitch in front and rear face plates arranged as positioning members for positioning a developing roller shaft and a photoconductor shaft in a process cartridge, and is well-known as conventional art.
As to the process cartridge, known is a process cartridge of a cantilever support in which a rotating shaft of a rotating member such as a conveying screw that rotationally conveys the developer protrudes from an outer surface of a housing of the process cartridge and a gear is attached to a distal end of the protruding rotating shaft (for example, refer to FIGS. 5 and 8 in Japanese Patent Application Laid-open No. 2007-047720).
In the process cartridge described above (hereinafter, simply referred to as a “cartridge” in some cases), when the cartridge is mounted on an apparatus main body, the gear meshes with a drive input gear or the like to which a rotational driving force is transmitted from the apparatus main body so as to be rotationally driven. Such a cartridge having the configuration as described above is of a cantilever support type in which the distal end of the protruding rotating shaft is not supported, so that a space in the longitudinal direction (rotating shaft direction) of the cartridge is advantageously secured, which is appropriate for reducing the size of the apparatus.
However, on the front and the rear face plates that couple a photoconductor unit and a developing unit, it is preferable that the developing roller shaft, the photoconductor shaft, and a portion that fixes a posture of the cartridge are on the same plane in terms of accuracy of components and/or the like. For example, driving components such as a gear are inside the face plates (for example, refer to FIG. 8 in Japanese Patent Application Laid-open No. 2007-047720), the face plates should be correspondingly shifted to the outside in the entire area, so that the corresponding space is occupied and the size of the apparatus is undesirably increased.
In view of such a situation, there is a need to provide a process cartridge for preventing the size of the apparatus from increasing.